1. Field of the Invention
The present invention relates to a developer filtering apparatus of printer, and more particularly, to a developer filtering apparatus of a printer for filtering developer discharged to a circulation tank from a developing unit.
2. Description of the Related Art
In a typical liquid electrophotographic printer, an electrostatic latent image formed on a photoreceptor such as a photoreceptor drum or photoreceptor web is developed with developer having a predetermined color, and the developed image is transferred to a print paper so that a desired image is printed. The liquid electrophotographic printer includes a developing unit for developing the electrostatic latent image formed on the photoreceptor web by supplying developer to the photoreceptor web and a developer supplying apparatus for continuously supplying developer having a predetermined concentration to the developing unit.
In a conventional printer, a developing unit includes a developing roller for developing an electrostatic latent image formed on a photoreceptor web by a laser scanning unit with developer in which toner having a predetermined color and liquid carrier are mixed in a predetermined ratio.
Also, the developer supplying apparatus includes a developer supply path connecting a circulation tank and a developing unit, a pump installed on the developer supply path, and an injection nozzle installed at the leading end of the developer supply path for injecting developer between a predetermined gap G between the developing roller and the photoreceptor web. The developing unit is connected to the circulation tank by a discharge pipe to collect developer remaining after being used for development in the developing unit. Thus, the developer contained in the circulation tank is circulated between the developing unit and the circulation tank in a range of concentration allowance.
During the above circulation process, the developer may contain impurities due to fixation of toner or intrusion of foreign materials. Accordingly, it is necessary to filter impurities by installing a filter on the paths. However, there is no filtering means on the path to the circulation tank.